1. Field of the Invention
The present invention relates to a mechanism having a simple structure in which neck injury of a passenger can be effectively prevented in the event of a rear-end collision of a car.
2. Description of the Related Art
When a rear-end collision has taken place due to a rear car during car driving, the car is rapidly accelerated, and the head of a vehicle occupant is rearwardly leant back, and thus the neck of the vehicle occupant is seriously injured. In this case, a headrest installed in an upper portion of a seat back supports the head (back of the head) of the vehicle occupant to reduce the degree of injury.
However, generally, the head of a passenger, in particular, the head of a driver is spaced apart from the headrest by a predetermined distance during car driving. Thus, in a rear-end collision, the headrest does not support the head of the passenger. Thus, the neck of the passenger is rapidly leant back and may be seriously injured.
In an attempt to solve this problem, headrest mechanisms in which a headrest is moved forwardly and upwardly (a direction in which the headrest is simultaneously moved forwardly and upwardly toward the back of the head of the passenger) and the head of the passenger is quickly supported so that injuries of the neck and a portion near the neck of the passenger can be prevented, have been developed.
However, general active headrest mechanisms have complicated structures and thus cause an increase in costs for a vehicle seat and a car.
Meanwhile, convenience devices such as inclination angle adjusting devices (swing devices) and forward and rearward position adjusting devices are added to recent high-grade car headrests so that the head of the passenger can be more comfortably supported according to various body conditions of passengers.
However, due to a limited space of the headrest, it is very difficult to additionally install the above-mentioned convenience devices in the above-described active headrest mechanisms.
Meanwhile, in the above-described active headrest mechanisms, the headrest may be slightly shaken with respect to the vehicle seat before the headrest operates, i.e., in an ordinary car driving state. This is because the headrest is not permanently secured to the vehicle seat of the car and needs to be quickly relatively moved from the vehicle seat in the event of a rear-end collision. Thus, the problem is a general phenomenon due to implementation of the active headrest mechanisms.
However, shake of the headrest causes inconvenience and anxiety to a user and noise and vibration and furthermore causes doubts about the quality of the vehicle seat and the car.